Local switch (Local Switch) refers to that a local call that starts and terminates at a same base station or a same group of base stations implements local switch in a wireless network, and may also refer to that a local call that starts and terminates at a same wireless controller (RNC (Radio Network Controller)/BSC (Base Station Controller), or a group of wireless controllers (RNC/BSC) connected to a same MSC (Mobile Switching Center)/SGSN (Serving GPRS SUPPORT NODE) implements local switch in a wireless network, bypassing a backhaul network in which mobile communication traffic is transmitted from a wireless base station to a nearest switch node. If a local switch technology is simply used to implement data transmission between user equipments under a same base station, all data transmission has to be forwarded by a network, resulting in a severe waste of resources in a communications network.
D2D communication (Device to Device communication) refers to direct communication between two terminals without forwarding user data by the network. D2D communication can improve system coverage and network capacity, reduce network construction costs and save precious air interface resources. How to apply D2D communication in an existing cellular network is a problem that needs to be solved.